Wnt canonical signaling plays critical roles in embryonic development and cell fate decisions and its constitutive activation has been directly implicated in human cancer. The noncanonical Wnt pathway, also importantly involved in development including planar cell polarity (PCP) and convergent extension, shares components with Wnt 2-catenin signaling including the Frizzled (Fz) receptors and Dishevelled (Dsh/Dvl). However, pathway signaling diverges downstream of Dsh/Dvl to activate strikingly different biochemical pathways and biological outcomes. This application investigates the molecular aspects of Wnt signaling specificity, taking advantage of complementary approaches and expertise involving both mammalian and Drosophila systems. Using a kinome shRNA screen we have identified two novel Dsh kinases, dWnk and dCDKL. Our preliminary studies indicate that these kinases specifically function in canonical and PCP pathways, respectively. In Aim 1, we propose to further characterize Drosophila Wnk kinase in Wnt-pathway specific responses. In Aim 2, we will investigate the role of mammalian Wnk kinases in Wnt canonical signaling and in Wnt-driven cancer cells. In Aim 3, we will characterize the role of CDKL kinases in Wnt-signaling pathway responses. These investigations should elucidate novel components of Wnt pathways, lead to a better understanding of the evolutionary conservation and/or divergence of Wnt pathway specification, and possibly identify new therapeutic targets for Wnt activated human tumor cells. Our efforts are enhanced by close collaborative interactions among investigators, whose expertise and interrelated efforts strongly complement and help to inform these investigations. PUBLIC HEALTH RELEVANCE: Wnt signaling pathways and associated regulatory factors have been implicated in many growth and patterning contexts and are linked to many diseases, ranging from ciliopathies and angiogenesis defects to cancer (e.g. several pathway components are tumor suppressors or proto-oncogenes). This proposal addresses critical aspects of Wnt pathway specification that are not yet elucidated, and the information acquired should significantly advance our understanding of Wnt signaling mechanisms in normal development and disease.